Switch-lock



H. P. LIVERSIDGE.

SWITCH LOCK.

APPLICATION FILED Aus.8. I918.

Patented Aug. 16, 1921.

ZSHEETS-SHEET 1. FIG. 2

U HWM I.

IN I/ENTOR WITNESS A TTORNEY UNITED STATES PATENT OFFICE.

SWITCH-LO CK.

Application filed August 8, 1918.

To tiller/10222 2? may concern:

Be it known that I, Hon-ion P. Livnizsmon, a citizenot the United States, residing at Bala, in the county oi Montgomery and State of Pennsylvania, have invented a certain new and useful Switch-Lock, of which the following is a specification.

My invention relates to switch locks for holding high tension switches in closed sition.

The main purpose or my invention is to place the bodily movable parts forming the jaws above the knife blade and preferably, beyond the contact clips, where the electromagnetic forces acting upon them will be least.

A further purpose is to lock the switch by j aws swinging laterally to the blade in planes perpendicular to the path of movement of the free end of the switch blade.

)1 further purpose is to swing the locking jaw or jaws of a switchlock about an axis approximately parallel to the direction of initial opening movement of the end of the switch blade.

A further purpose is to wedge locking jaws open by cam operation of a switchblade release handle.

Sr further purpose is to hold a switch blade in closed position by laterally swinging spring-pressed jaws and to release them by othcenter pressure upon them in the reverse direction to the spring pressure, exerted by a member upon the end of the switch.

Further purposes will appear in the specilication and the claims thereof.

I ha to preferred to illustrate my invention by but one form tnereoi', selectin among the many in which it may appear, a form which has proved in ope adieu to be practicable. etlicient and thoroughly reliable and which at the same time well illustrates the princigles of my invention.

Figure l is a front elevation of a switch and switch lock embodying this preferred form.

Fig. 2 is a section upon line 2-2 of Fig. 1. Fig. 2 is a side elevation of an operating har used in releasing the switch.

Fig. 3 is an enlarged view of a part of the structure in Fig. 1. one side being sectioned.

Fig. l is a broken front elevation of a part ot Fig. 1. showing the locking jaws in opened position.

Specification of Letters Patent.

Patented Aug. 16', 1921. Serial No. 248,853.

Fig. 5 is a broken upon line 5-5.

Fig. 6 is a section of Fig. 5, taken upon the line 66 thereof.

Similar numerals indicate like parts in the drawings.

My invention is shown as applied to high tension switches of a type in which the blade when in closed position frequently lies vertically and substantially parallel to the switch board, though the position of the switch obviously'does not affect the invention.

The switch blade 11 is shown as pivoted at 12, in terminal 13 and as seating in closed position within the oppositely placed fingers of spring contact 1% upon terminal 15.

' With the very heavy currents which may pass through such a switch, in case of a short-circuit, there are correspondingly powerful electromagnetic stresses exerted at right angles to the direction of current flow.

The directions of these forces, in so far as they need be considered here, are indicated by the arrows 0-0, (F ig. 5) and bb, (Fig. 3) perpendicular to the direction of current flow in the knife bladeof the switch, and a-c, (Fig. 5) perpendicular to the direction of current flow in the contacts.

Of these the effective force'in the plane of switch opening alone tends to open the switch knife and the others have hitherto been largely disregarded.

Most of the switch locks attempted to prevent improper opening'of the switch by electromagnetic forces have either wholly disregarded other electromagnetic forces than those opening the switch or have overlooked the corresponding electromagnetic forces upon electrically conducting lock arms or parts parallel to the direction of current flow.

In the prior art swinging jaws and other lock members movable transversely to their lengths have been placed freely in position to parallel the direction of current in the switch blade or contact and to carry current in this position. The parallel currents in the blade or contactand in these members have developed electromagnetic stresses tending to open the locks.

Most of these locksare further objectionable because they form more latches or hooks upon the blade, engaging the fixed structure beneath or beside it, or because, being section of Fig. 3 taken pivoted on an axis or axes parallel with or directly across the closed position of the length of the blade they are subject to direct and powerful electromagnetic opening stresses, too slight swinging movement will release them and the wedge-opening strain of the switch blade renders them untrustworthy. One type has failed because of the fact that it used straight line sliding movement for the release and engagement and was particularly unreliable because of the extent of sliding movement which its construction required.

I aim to reduce the tendency of the switch blade when pressed outwardly to open the look by pivoting the look upon an axis substantially tangential to an arc of movement of the switch blade in final closing or initial opening movement, so that the pressure against the movable lock member shall be substantially parallel with the axis upon which the lock member is pivoted and there will be no turning movement or a minimum turning movement thereabout.

Describing in detail the construction that is illustrated, but recognizing that it may be greatly varied, while still obtaining a part, at least, of the benefit of my invention :I mount two locking jaws 16 and 17 upon pivot pins or bolts 18 and 19, perpendicular to the base of the fitting or terminal 15.

The pins are secured to the base by plate 20 held by screw 21.

The pins 18 and 19 are enlarged and screw threaded at the ends, and are inserted from the bottom'before the plate 20 is applied. They screw into it and are thus rigidly connected with it. The bearings shown for the locking jaws 16 and 17, upon which they turn about the pins 18 and 19, are provided by cylindrical extensions 23, preferably integral with the respective jaws and fitting the lower ends of the pivot pins as at 24.

For a purpose more fully hereinafter indicated, the cylindrical extensions 23 are provided with lever arms 25 which are con- 'veniently formed by opening (unfolding) the extensions for a part of their lengths along their adjoining (inner) sides, as at 26 so that these bordering edges form tangential operating arms.

The two cylindrical extensions are oppo sitely counter-part, in that they have the two tangential edges extending in opposite angular directions, so as to lie toward each other, as best seen in Figs. 3, 4 and 6.

Each of the bearings is spaced at the bottom from the plate 20, by a washer 27.

For the purpose. of providing torsion to maintain the locking jaws normally in a closed position as shown in Figs. 1 and 6 and at the right hand in Fig. 3, a spiral spring 28 is used and the bearings are counter bored at 29 to give room for the springs. The latter are held under tension by connection at one end each with the fixed pins, as at 30, and at their opposite ends 31 with the edges 32 of the open part of the cylindrical extensions.

In order to give hearing at the outer end as well as at the inner end about the outer ends of the fixed pins, bushings 33 are in serted. Longitudinal movement of the bearings upon the pins is stopped by nuts 34 and cotter pins 35 upon and through the threaded outer ends of the pins.

The switch blade 11 is tapered upon its inner edge as at 37 where it engages the normally closed locking jaws 16 and 17. The jaws are chamfered as at 36 to cooperate, resulting in automatic opening of the jaws to allow the blade to pass through.

The switch blade carries a ring 38 at its outer end, apertured at 39 for manipulation by means of pin 10 on a pole 41. This is used for both closing and opening movements of the blade.

For the closing movement the blade is shoved into position, using the ring as a mere handle. For opening movement the ring is used to open the locking jaws by pressure upon the lever arms 25.

The most convenient means for causing this pressure upon the arms is by bifurcating the inner end of the ring to form ears 42 adapted to straddle the knife, pivoting the ring to the knife by the ears, as at 43, and providing the ears with cam noses d4: outside of the pivot point. Swinging movement of the ring can readily be limited by its engagement with the end of the knife. A conformation to fit the usual end of the knife, as shown in both positions of the ring is seen in dotted lines at 45.

It will be noted that the cylindrical bearings upon whose upper ends the locking jaws are carried are not bodily movable in any direction but turnmerely about their axes X, X, and that the electromagnetic stresses upon them by reason of currents in them and in the switch parts have no lock opening effect. These bearings therefore for all practical purposes can be eliminated from consideration of the electromagnetic lock-opening stresses.

The position of the locking jaws 7 and 8 wholly outside of the knife blade and on the other side of the contact from the pivot (though my invention would be advantageous also in other locations than the one shown) greatly reduces the electromagnetic forces upon these jaws. If the locking plates be located beyond the contacts (that is above an end of the switch extended past the contacts) and be of magnetizable material, electromagnetic forces will be exerted upon the plates in the direction of the end of the switch-blade tending to force them tightly together.

If the locking plates be located between the contacts 14: and the pivot 12, the electromagnetic forces exerted upon the locking plates will be substantially as indicated in Fig. 6 where stress indicated by arrows 0' will be exerted upon the plates as well as the resultant stresses shown by arrows at (.7. As will be observed, my locking plates are subject to minimal stress only and are free from the opening efiort of the major electromagnetic stresses indicated by Z) in Fig. 3 which have proved so destructive to other terms of locking mechanisms.

Il herever the diagonal locking plates are located, and whatever their material, any current passing through them will flow in multiple and the current through each will react upon the current in the other to draw the two plates together and hold them in locked position.

The small size, small extent of bodily movement and position on the opening side of the knife blade all combine to reduce the electromagnetic opening stresses upon the locking plates and in certain positions of the lock these stresses may be made "to hold the plates in closed position.

It must be remembered that the nearer the jaws approach the straight line position between the axe, the greater will be the opening movement required to release the knife and the less leverage the knife blade exerts in automatic opening of the locking jaws as the switch is closed; and that the larger the angles which the jaws make with the line X X. the smaller the angular movement required for opening.

Having given the main bases upon which design of these locking bars must be predirated, I consider the vari.. as in the design of the jaws for special uses or to suit the views and preferences of different designers to be purely within the range of ordinary design and feel that further discussion here will not be necessary.

In operation. the locking and uniocking movements of the switch both take place automatically as the switch knife is closed and opened by means of the pole. The tapered edges of the knife blade and of the locking jaws cooperate to open the jaws to advantage as the knife blade strikes them and they close automatically by spring torsion. With opening pull upon the ring the noses st first press the arms 25 inwardly. releasing the lock. and then hold the parts in this posi ion while the knife blade is being at least partially withdrawn.

Having thus desc ibed my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a switch lock, a knife switch blade,

a contact engaged by the blade, a locking jaw adapted to swing into the path of 0pening movement of the blade and pivotal mounting for the jaw pa 'alleling the direction of initial opening switch blade movement.

2. In a switch lock, a knife switch blade, at contact engaged by the blade, a locking jaw adapted to swing into the path of opening movement of the blade and rest in diagonal position, sloping toward the contact and pivotal mounting for the jaw paralleling the direction of initial opening switch blade movement.

3. In a switch lock, a knife switch blade, a contact therefor, a pair of locking jaws movable across the opening path of movement of the blade from opposite sides thereof and pivotal mounting for the jaws hav ing axcs tangent to the direction of initial opening movement of the blade.

4. In a switch lock, a knife switch blade, a contact engaged by the blade, a pair of locking aws movable into the path of opening movement of the blade and diagonal to the length of the blade when in locked position, pivotal mounting for the jaws parallel to the width of the blade and means for resiliently holding the jaws in locked position.

5. In a switch lock, a knife switch blade, a contact therefor. a locking jaw diagonal toward the contact to the direction of length of the blade, pivotal mounting for the aw having an axis tangent to the direction of initial opening movement of the blade and resilient means for normally holding the blade in closed position.

6. In a switch lock, a knife switch blade, in combination with a contact therefor and a locking jaw bodily located on the opening side of the blade and bodily movable from the side over the path of withdrawal movement of the blade outside the blade.

7. In a switch lock, a knife switch blade, :1 locking jaw therefor and pivotal mounting for the jaw having its axis at one side of the jaw and extending parallel to the line of initial opening movement of the blade.

In a switch lock. a knife switch blade, :1 contact engaged thereby and a pivoted locking jaw extending, in locked position. diagonally to the length of the blade and into its path of movement.

9. In a switch look. a knife switch blade, a contact engaged thereby and a pivoted locking jaw extending from the pivot at the side of the blade diagonally across the direction of opening movement of the blade and in a direction generally reverse to the resultant of electromagnetic t'orces upon the jaw.

10. In a switch lock, a knife switch blade, a contact engaged thereby, a pair of locking jaws adapted to swing into the path of opening movement ofv the blade from opposite sides thereof, pivotal mounts therefor generally parallel to the direction of initial opening movement of the blade, and springclosing means for turning the jaws about their pivots to lock the switch.

11. In a switch lock, a knife switch blade, a contact engaged thereby and a pivoted locking aw extending into the path of opening movement of the blade and having the resultant of electromagnetic forces upon the jaw tending to hold the jaw closed.

12. In a switch lock, a knife switch blade, a contact engaged thereby, a pair of revoluble locking jaws in closed position extending from opposite sides over the path of opening movement of the blade, subject to electromagnetic stresses transversely perpendicular to the blade tending to separate them and longitudinally of the blade away from the contact, the jaws extending generally in reverse directions to the resultants of the electromagnetic forces thereof and pivots for said jaws having axes tangent to the direction of initial opening switch blade movement.

13. In a switch lock, a knife switch blade, a contact engaged thereby, a pair of locking jaws wholly on the outer side of the blade, and bearings for the jaws extending in planes parallel to the width of the knife switch blade.

14. In a switch lock, a knife switch blade, a contact engaged thereby, a revoluble locking jaw extending into the path of opening movement of the blade, a pivot pin for the jaw, a cylindrical bearing for the jaw about the pin and a spiral spring inside the bearing and about the pin tending to hold the jaw in closed position.

15. In a switch lock, a knife switch blade, a contact engaged thereby, a pivot pin, a locking jaw adapted to move thereabout, a bearing for the jaw about the pin, spring means for holding the jaw normally in looking position, a member connected with the bearing and projecting relatively thereto, an opening ring for switch withdrawal and a projection on the ring engaging the projection on the bearing to overcome the spring locking tension upon the jaw when the ring is pulled to withdraw the blade.

16. In a switch lock, a knife switch blade, a contact engaged by the blade, a pin fixed beside the closed position of the blade, paral lel to a tangent to its initial opening movement, a switch lock having a bearing extending over the pin and enlarged through a part of the length of the bearing, and a spring within the enlargement engaging the bearing and pin to normally hold the lock closed, the bearing engaging the pin both above and below the spring.

17. In a switch lock, a knife switch blade, a contact engaged by the blade, a pin fixed beside the closed position of the blade parallel to a tangent to its initial opening movement, a switch lock having a bearing extending over the pin and enlarged through a part of the length of the bearing, a spring within the enlargement engaging the bearing and pin to normally hold the lock closed, the bearing engaging the pin both above and below the spring, an extension of the bearing toward the switch blade, a ring carried by and movable with respect to the end of the blade and a projection upon the ring adapted to engage the extension carried by the bearing with opening tension upon the blade to rotate the bearing, revolving the lock to release the switch knife.

18. In a switch look, a base, a knife switch blade and a contact engaged thereby mounted upon the base, the blade extending beyond the contact, a rotatable switch lock mounted upon the base, having lockingjaws on the outer side of the blade in the closed position of the latter and release members extending toward the blade and located between the jaws and the base, in combination with'an opening member for the switch lock carried by the blade and engaging the release members to open the lock.

19. In a switch lock, a knife blade movable in a vertical plane, a contact, a locking member beyond the contact, rotatable in a plane parallel to the length of the blade and arranged to engage the blade beyond the contact, and an unlocking device carried by the end of the blade.

20. In a switch look, a knife switch blade, :1 contact therefor, a locking jaw pivoted to swing laterally to the blade, spring closing means for the jaw and a lock opening device carried by the blade.

21. In a switch lock, a knife switch blade, a contact engaged by the blade and a pair of locking jaws rotatable from the sides into the path of movement of the blade and having the lengths of the locking jaws diagonal to the blade in the direction of the contact.

22. In a switch look, a knife switch blade, a contact engaged by the blade, a pair of locking jaws rotatable from the sides into the path of movement of the blade and having the lengths of the locking jaws diagonal to the blade on the side of the pivots thereof toward the contact, off-center release arms for the jaws projecting generally toward the blade and cooperating release mechanism carried by the blade and engaging it.

23. In a switch look, a knife switch blade, a lock pivot extending beyond the blade in its direction of opening movement when the blade is in closed position and a laterally movable locking plate pivoted thereon and adapted to swing into the path of opening movement of the blade.

24. In a switch look, a knife switch blade, a pair of lock pivots on opposite sides thereof, extending beyond the blade in the latters direction of opening movement when the blade is in closed position and a pair of laterally swinging locking plates, one on each pivot, adapted to swing toward each other and meet in diagonal positions with 10 respect to a line joining the pivots.

25. In a switch lock, a knife switch blade, in combination with a pair of locking plates on opposite sides thereof, movable in planes outside of the closed position of the blade 15 and meeting over it.

HORACE P. LIVERSIDGE. 

